.page-about {
  --about-line: rgba(42, 52, 66, 0.8);
  --about-blob: 46% 54% 58% 42% / 52% 44% 56% 48%;
  display: block;
  color: var(--cream);
  background: var(--ink);
}

.page-about .about-crumb {
  padding-top: 22px;
}

/* ---------- Hero ---------- */

.page-about .about-hero {
  position: relative;
  overflow: hidden;
  padding: 24px 0 56px;
}

.page-about .about-hero::before {
  content: "";
  position: absolute;
  top: -170px;
  right: -160px;
  width: 420px;
  height: 420px;
  border-radius: 50%;
  background: radial-gradient(circle at 38% 38%, rgba(255, 107, 26, 0.55), rgba(255, 107, 26, 0) 70%);
  pointer-events: none;
}

.page-about .about-hero::after {
  content: "";
  position: absolute;
  bottom: -120px;
  left: -140px;
  width: 340px;
  height: 300px;
  border-radius: var(--about-blob);
  background: radial-gradient(circle at 60% 40%, rgba(0, 229, 255, 0.18), rgba(0, 229, 255, 0) 72%);
  pointer-events: none;
}

.page-about .about-hero__inner {
  position: relative;
  z-index: 1;
}

.page-about .about-hero__title {
  margin: 18px 0 0;
  font-family: var(--font-display);
  font-weight: 200;
  font-size: clamp(2.6rem, 11.5vw, 7rem);
  line-height: 0.98;
  letter-spacing: -0.015em;
  color: var(--cream);
}

.page-about .about-hero__lede {
  margin: 26px 0 0;
  max-width: 56ch;
  font-size: 1.0625rem;
  line-height: 1.8;
  color: var(--mist);
}

.page-about .about-hero__stats {
  list-style: none;
  margin: 38px 0 0;
  padding: 0;
  display: grid;
  grid-template-columns: repeat(2, minmax(0, 1fr));
  gap: 1px;
  background: var(--steel);
  border-radius: var(--radius);
  overflow: hidden;
}

.page-about .about-hero__stats li {
  background: var(--ink-2);
  padding: 16px 18px;
  display: flex;
  flex-direction: column;
  gap: 6px;
}

.page-about .about-hero__num {
  font-family: var(--font-mono);
  font-weight: 700;
  font-size: 1.5rem;
  letter-spacing: -0.01em;
  color: var(--flame);
}

.page-about .about-hero__label {
  font-size: 0.8125rem;
  line-height: 1.5;
  color: var(--mist);
}

/* ---------- 章节索引 ---------- */

.page-about .about-menu {
  margin-top: 46px;
  padding-top: 20px;
  border-top: 1px solid var(--about-line);
}

.page-about .about-menu__head {
  margin: 0 0 14px;
  font-family: var(--font-mono);
  font-size: 0.6875rem;
  letter-spacing: 0.2em;
  text-transform: uppercase;
  color: var(--mist);
}

.page-about .about-menu__list {
  list-style: none;
  margin: 0;
  padding: 0;
  display: grid;
  grid-template-columns: repeat(2, minmax(0, 1fr));
  gap: 2px 20px;
}

.page-about .about-menu__list a {
  display: flex;
  align-items: baseline;
  gap: 10px;
  padding: 9px 2px;
  color: var(--cream);
  text-decoration: none;
  font-size: 0.9375rem;
  border-bottom: 1px solid transparent;
  transition: color 0.2s ease, border-color 0.2s ease;
}

.page-about .about-menu__list a:hover,
.page-about .about-menu__list a:focus-visible {
  color: var(--cyan);
  border-color: var(--cyan);
}

.page-about .about-menu__idx {
  font-family: var(--font-mono);
  font-size: 0.75rem;
  color: var(--flame);
}

/* ---------- 章节通用 ---------- */

.page-about .about-chapter {
  padding: 52px 0;
  border-top: 1px solid var(--about-line);
}

.page-about .about-chapter--band {
  background: var(--ink-2);
}

.page-about .about-chapter__grid {
  display: grid;
  grid-template-columns: 1fr;
  gap: 14px;
}

.page-about .about-chapter__aside {
  align-self: start;
}

.page-about .about-chapter__idx {
  font-family: var(--font-mono);
  font-weight: 700;
  font-size: 1.75rem;
  letter-spacing: 0.06em;
  color: var(--flame);
  opacity: 0.85;
}

.page-about .about-chapter__title {
  margin: 0 0 20px;
  font-family: var(--font-display);
  font-weight: 200;
  font-size: clamp(1.75rem, 6vw, 3rem);
  line-height: 1.12;
  letter-spacing: -0.01em;
  color: var(--cream);
}

.page-about .about-chapter__body p {
  margin: 0 0 18px;
  font-size: 1rem;
  line-height: 1.85;
  color: rgba(245, 241, 232, 0.82);
  max-width: 62ch;
}

.page-about .about-chapter__intro {
  font-size: 1.0625rem !important;
  color: var(--cream) !important;
}

.page-about .about-chapter__tail {
  margin-top: 26px !important;
  padding-left: 16px;
  border-left: 2px solid var(--cyan);
  color: var(--mist) !important;
}

.page-about .about-figure {
  margin: 30px 0 0;
}

.page-about .about-figure .media {
  border-radius: var(--radius-lg);
  overflow: hidden;
}

.page-about .about-figure img {
  display: block;
  width: 100%;
  max-width: 100%;
  height: auto;
  object-fit: cover;
  border-radius: var(--radius-lg);
}

.page-about .about-figure .media__caption {
  margin-top: 12px;
  font-size: 0.8125rem;
  color: var(--mist);
}

/* ---------- 时间线 ---------- */

.page-about .timeline {
  list-style: none;
  margin: 26px 0 0;
  padding: 0;
}

.page-about .timeline__item {
  position: relative;
  padding: 0 0 30px 28px;
  border-left: 2px solid var(--steel);
  transition: border-color 0.25s ease;
}

.page-about .timeline__item::before {
  content: "";
  position: absolute;
  left: -7px;
  top: 5px;
  width: 12px;
  height: 12px;
  border-radius: 50%;
  background: var(--flame);
  box-shadow: 0 0 0 4px rgba(255, 107, 26, 0.16);
  transition: background 0.25s ease, box-shadow 0.25s ease;
}

.page-about .timeline__item:last-child {
  padding-bottom: 0;
  border-left-color: transparent;
}

.page-about .timeline__item:hover::before,
.page-about .timeline__item:focus-within::before {
  background: var(--cyan);
  box-shadow: 0 0 0 6px rgba(0, 229, 255, 0.18);
}

.page-about .timeline__item:hover {
  border-left-color: var(--cyan);
}

.page-about .timeline__stage {
  margin: 0 0 6px !important;
  font-family: var(--font-mono);
  font-size: 0.6875rem !important;
  letter-spacing: 0.18em;
  text-transform: uppercase;
  color: var(--amber) !important;
}

.page-about .timeline__head {
  margin: 0 0 8px;
  font-family: var(--font-display);
  font-weight: 400;
  font-size: 1.125rem;
  line-height: 1.4;
  color: var(--cream);
}

.page-about .timeline__item--now .timeline__stage {
  color: var(--lime) !important;
}

.page-about .timeline__item--now::before {
  background: var(--lime);
  box-shadow: 0 0 0 4px rgba(57, 255, 136, 0.18);
}

.page-about .timeline__item p {
  margin: 0 !important;
  font-size: 0.9375rem !important;
  line-height: 1.8 !important;
}

/* ---------- 团队双栏 ---------- */

.page-about .split {
  display: grid;
  grid-template-columns: 1fr;
  gap: 20px;
  margin-top: 6px;
}

.page-about .split__col {
  padding: 20px 0 20px 20px;
  border-left: 2px solid var(--steel);
}

.page-about .split__head {
  margin: 0 0 8px;
  font-family: var(--font-display);
  font-weight: 400;
  font-size: 1.0625rem;
  color: var(--flame);
  letter-spacing: 0.01em;
}

.page-about .split__col p {
  margin: 0 !important;
  font-size: 0.9375rem !important;
}

/* ---------- 引文 ---------- */

.page-about .quote {
  margin: 26px 0 28px;
  padding: 26px 22px;
  border-radius: var(--radius-lg);
  background: linear-gradient(135deg, rgba(255, 107, 26, 0.16), rgba(122, 92, 255, 0.12));
}

.page-about .quote p {
  margin: 0 !important;
  font-family: var(--font-display);
  font-weight: 200;
  font-size: clamp(1.125rem, 3.6vw, 1.5rem);
  line-height: 1.65;
  color: var(--cream) !important;
  max-width: 46ch;
}

.page-about .voice-grid {
  display: grid;
  grid-template-columns: 1fr;
  gap: 16px;
}

.page-about .voice-grid__item h3 {
  margin: 10px 0 8px;
  font-family: var(--font-display);
  font-weight: 400;
  font-size: 1.0625rem;
  color: var(--cream);
}

.page-about .voice-grid__item p {
  margin: 0 !important;
  font-size: 0.9375rem !important;
}

/* ---------- 设备与服务版图 ---------- */

.page-about .device-grid {
  display: grid;
  grid-template-columns: 1fr;
  gap: 2px;
  margin: 24px 0 0;
  background: var(--steel);
  border-radius: var(--radius);
  overflow: hidden;
}

.page-about .device-grid__card {
  background: var(--ink-3);
  padding: 18px 20px;
}

.page-about .device-grid__label {
  margin: 0 0 6px !important;
  font-family: var(--font-mono);
  font-size: 0.75rem !important;
  letter-spacing: 0.16em;
  text-transform: uppercase;
  color: var(--cyan) !important;
}

.page-about .device-grid__text {
  margin: 0 !important;
  font-size: 0.9375rem !important;
  line-height: 1.75 !important;
}

/* ---------- 数据 ---------- */

.page-about .metric {
  list-style: none;
  margin: 24px 0 0;
  padding: 0;
  display: grid;
  grid-template-columns: 1fr;
  gap: 0;
}

.page-about .metric__item {
  display: flex;
  flex-direction: column;
  gap: 4px;
  padding: 18px 0;
  border-bottom: 1px solid var(--about-line);
}

.page-about .metric__item:first-child {
  border-top: 1px solid var(--about-line);
}

.page-about .metric__num {
  font-family: var(--font-mono);
  font-weight: 700;
  font-size: 1.875rem;
  line-height: 1.1;
  letter-spacing: -0.02em;
  color: var(--cream);
}

.page-about .metric__unit {
  margin-left: 3px;
  font-size: 0.9375rem;
  font-weight: 500;
  color: var(--flame);
}

.page-about .metric__label {
  font-size: 0.875rem;
  line-height: 1.6;
  color: var(--mist);
}

/* ---------- 章节引导链接 ---------- */

.page-about .about-links {
  display: grid;
  grid-template-columns: 1fr;
  gap: 12px;
  margin-top: 28px;
}

.page-about .about-link {
  display: flex;
  flex-direction: column;
  gap: 6px;
  padding: 20px 22px;
  border-radius: var(--radius);
  background: var(--ink-2);
  text-decoration: none;
  transition: background 0.25s ease, transform 0.25s ease;
}

.page-about .about-link:hover,
.page-about .about-link:focus-visible {
  background: var(--ink-4);
  transform: translateY(-2px);
}

.page-about .about-link__head {
  font-family: var(--font-display);
  font-weight: 400;
  font-size: 1.0625rem;
  color: var(--flame);
}

.page-about .about-link__desc {
  font-size: 0.875rem;
  line-height: 1.65;
  color: var(--mist);
}

/* ---------- 桌面端 ---------- */

@media (min-width: 768px) {
  .page-about .about-hero {
    padding: 34px 0 78px;
  }

  .page-about .about-hero__stats {
    grid-template-columns: repeat(4, minmax(0, 1fr));
  }

  .page-about .about-menu__list {
    grid-template-columns: repeat(3, minmax(0, 1fr));
  }

  .page-about .about-chapter {
    padding: 78px 0;
  }

  .page-about .about-chapter__grid {
    grid-template-columns: 96px minmax(0, 1fr);
    gap: 32px;
  }

  .page-about .about-chapter__aside {
    position: sticky;
    top: 32px;
  }

  .page-about .about-chapter__idx {
    font-size: 2.25rem;
  }

  .page-about .split {
    grid-template-columns: repeat(2, minmax(0, 1fr));
    gap: 28px;
  }

  .page-about .voice-grid {
    grid-template-columns: repeat(3, minmax(0, 1fr));
    gap: 24px;
  }

  .page-about .device-grid {
    grid-template-columns: repeat(2, minmax(0, 1fr));
  }

  .page-about .metric {
    grid-template-columns: repeat(2, minmax(0, 1fr));
    column-gap: 40px;
  }

  .page-about .metric__item:nth-child(2) {
    border-top: 1px solid var(--about-line);
  }

  .page-about .about-links {
    grid-template-columns: repeat(2, minmax(0, 1fr));
    gap: 16px;
  }

  .page-about .about-figure {
    margin-top: 40px;
  }
}

@media (min-width: 1080px) {
  .page-about .about-chapter__grid {
    grid-template-columns: 132px minmax(0, 1fr);
    gap: 48px;
  }

  .page-about .about-chapter__idx {
    font-size: 2.75rem;
  }

  .page-about .about-hero__title {
    font-size: clamp(4rem, 8.5vw, 7.5rem);
  }

  .page-about .metric {
    grid-template-columns: repeat(3, minmax(0, 1fr));
  }

  .page-about .metric__item:nth-child(3) {
    border-top: 1px solid var(--about-line);
  }

  .page-about .device-grid {
    grid-template-columns: repeat(4, minmax(0, 1fr));
  }
}

@media (prefers-reduced-motion: reduce) {
  .page-about .about-link,
  .page-about .timeline__item,
  .page-about .timeline__item::before {
    transition: none;
  }
}